McDonald's franchises near Tulsa, Oklahoma, have joined mobile marketing company Gamut Industries to develop Mobile Whoa - a campaign that offers consumers mobile coupons, an SMS scavenger hunt and a mobile phone picture gallery, writes Adrants (via MediaBuyerPlanner).

To join the hunt, participants can text "hunt 62931" or go to the website. Clues will be revealed until someone solves the mystery.

The coupons, called mCoups, will be available starting April 17 and will offer a free small order of fries or hash browns. People who upload photos can access the mobile phone picture directory, ring tones and wallpapers.